1. Technical Field
The present invention relates to a printing control apparatus and a printing control method.
2. Related Art
When band printing is performed by using a serial printer, banding (such as a streak pattern due to contrasting density of an ink) sometimes occurs in a joint portion between adjacent band portions because of error in transportation of a printing medium, or the like. With respect to such a problem, partially overlapping (POL) printing is well known. In this POL printing, subsequent to printing on a single band portion through a single scanning operation performed by a printing head, printing paper is transported in a sub-scanning direction by a distance smaller than the length of a sub-scanning-direction width of the single band portion, and printing on a next single band portion is performed through a next single scanning operation performed by the printing head. The occurrences of such banding are reduced by providing a POL area on which printing is performed through two scanning operations.
In such a POL area, a white streak occurs when landing positions of an ink are misaligned (this “landing” means adherence of an ink droplet discharged through a nozzle onto a printing medium). Reasons for such misalignments of the landing positions are airflow caused by an operation of a printing head, error in transportation of a printing medium, nozzle characteristics, alignment error, and the like. Particularly, in an area where color density is high (for example, an area where a landing amount of a black ink is large), the white streak is likely to be highly visible.
Here, in order to reduce the occurrences of such a white streak, a method of increasing an amount of an ink to be landed on the POL area is conceived. In this case, however, a black streak becomes likely to occur. Particularly, in an area where color density is low (for example, an area where a landing amount of a black ink is small), the black streak is likely to be highly visible.
In addition, the white streak is not limited to a streak in a white color, but its meaning also includes a streak in a color lighter than surrounding colors. Further, the black streak is not limited to a streak in a black color, but its meaning also includes a streak in a color darker than surrounding colors.
In addition, a related technology is described in JP-A-2007-245656.